• ETRI Journal
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• v.24 no.1
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• pp.43-55
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• 2002

This paper proposes a flow-based admission control algorithm through an Asynchronous Transfer Mode (ATM) based Multi-Protocol Label Switching (MPLS) network for multiple service class environments of Integrated Service (IntServ) and Differentiated Service (DiffServ). We propose the Integrated Packet Scheduler to accommodate IntServ and Best Effort traffic through the DiffServ-aware MPLS core network. The numerical results of the proposed algorithm achieve reliable delay-bounded Quality of Service (QoS) performance and reduce the blocking probability of high priority service in the DiffServ model. We show the performance behaviors of IntServ traffic negotiated by end users when their packets are delivered through the DiffServ-aware MPLS core network. We also show that ATM shortcut connections are well tuned with guaranteed QoS service. We validate the proposed method by numerical analysis of its performance in such areas as throughput, end-to-end delay and path utilization.

• Journal of Integrative Natural Science
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• v.11 no.4
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• pp.192-196
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• 2018

The mobile agent paradigm can be exploited in a variety of ways, ranging from low-level system administration tasks to middle ware to user-level applications. Mobile agents can be useful in building middle-ware services such as active mail systems, distributed collaboration systems, etc. An active mail message is a program that interacts with its recipient using a multimedia interface, and adapts the interaction session based on the recipient's responses. The mobile agent paradigm is well suitable to this type of application, since it can carry a sender-defined session protocol along with the multimedia message. Mobile agent communication is possible via method invocation on virtual references. Agents can make synchronous, one-way, or future-reply type invocations. Multicasting is possible, since agents can be aggregated hierarchically into groups. A simple check-pointing facility has also been implemented. Another proposed solution is to use multi agent computer systems to access, filter, evaluate, and integrate this information. We will present the overall architectural framework, our agent design commitments, and agent architecture to enable the above characteristics. Besides, the each information needed a mobile agent system such as text, graphic, image, audio and video etc, constructed a great capacity multimedia database system. However, they have problems in establishing connections over multiple subnetworks, such as no end-to-end connections, transmission delay due to ATM address resolution, no QoS protocols. We propose a new connection management scheme in the thesis to improve the connection management involved of mobile agent systems.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.915-918
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• 2009

다중 네트워크 인터페이스 단말과 멀티 네트워크 환경간의 통신을 위한 네트워크 구조에 관한 기존 연구는 GLL, A-MAC처럼 멀티네트워크 자원관리에 초점을 둔 프로토콜 연구가 대부분이며 이 프로토콜들은 2.5 계층, 즉, 네트워크 계층과 데이터 링크 계층 사이에 위치하여 응용을 위해서 다중 인터페이스 중 하나의 인터페이스를 선택할 수 있는 기능을 제공한다. 따라서 기존 연구에 초점은 기존 통신 프로토콜 및 인터넷 구조의 변화를 최소화 할 수 있으나 단말내의 응용이 다중 네트워크 인터페이스를 효율적으로 사용할 수 있는 기술은 아니다. 본 연구에서는 기존 통신 프로토콜 및 인터넷 구조에서 단말이 다중 네트워크 인터페이스 사용 시 발생하는 계층별 문제점 및 IETF MIF WG 표준화 동향을 분석한다. 특히 응용 계층이 멀티 네트워크 인터페이스 기반의 멀티 연결을 지원하지 못하는 문제점, 전송 계층에서의 다중 연결 시 발생하는 문제점, 네트워크 계층에서 다중 인터페이스별로 할당된 IP 주소에 대한 처리문제, 다중 인터페이스 라우팅 문제, Split DNS 문제, 응용별 서비스 요구에 적응적인 인터페이스 선택 방법에 관한 문제를 정의하고 이를 해결하기 위한 연구 방향을 제시한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.1
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• pp.195-215
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• 2021

Multipath Transport Control Protocol (MPTCP) is a transport layer protocol that enables multiple TCP connections across various paths. Due to path heterogeneity, it incurs more energy in a multipath wireless network. Recent work presents a set of approaches described in the literature to support systems for energy consumption in terms of their performance, objectives and address issues based on their design goals. The existing solutions mainly focused on the primary system model but did not discourse the overall system performance. Therefore, this paper capitalized a novel stochastically multipath scheduling scheme for data and path capacity variations. The scheduling problem formulated over MPTCP as a stochastic optimization, whose objective is to maximize the average throughput, avoid network congestion, and makes the system more stable with greater energy efficiency. To design an online algorithm that solves the formulated problem over the time slots by considering its mindrift-plus penalty form. The proposed solution was examined under extensive simulations to evaluate the anticipated stochastic optimized MPTCP (so-MPTCP) outcome and compared it with the base MPTCP and the energy-efficient MPTCP (eMPTCP) protocols. Simulation results justify the proposed algorithm's credibility by achieving remarkable improvements, higher throughput, reduced energy costs, and lower-end to end delay.

• Journal of Internet Computing and Services
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• v.10 no.4
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• pp.199-211
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• 2009

Recent advancements in wireless networks have enabled support for mobile applications to transfer data over heterogeneous wireless paths in parallel using data striping technique [2]. Traditionally, high performance data transfer requires tuning of multiple TCP sockets, at sender's end, based on bandwidth delay product (BDP). Moreover, traditional techniques like Automatic TCP Buffer Tuning (ATBT), which balance memory and fulfill network demand, is designed for wired infrastructure assuming single flow on a single socket. Hence, in this paper we propose a buffer tuning technique at senders end designed to ensure high performance data transfer by striping data at transport layer across heterogeneous wireless paths. Our mechanism has the capability to become a resource management system for transport layer connections running on multi-homed mobile host supporting features for wireless link i.e. mobility, bandwidth fluctuations, link level losses. We show that our proposed mechanism performs better than ATBT, in efficiently utilizing memory and achieving aggregate throughput.

• Structural Engineering and Mechanics
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• v.18 no.2
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• pp.247-262
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• 2004

In the earlier application of the spline finite strip method(FSM), the uniform B3-spline functions were used in the longitudinal direction while the conventional interpolation functions were used in the transverse direction to construct the displacement filed in a strip. To overcome the shortcoming of the uniform B3-spline, non-periodic B-spline was developed as the displacement function. The use of non-periodic B3-spline function requires no tangential vectors at both ends to interpolate the geometry of shell and the Kronecker delta property is also satisfied at the end boundaries. Recently, non-periodic spline FSM which was modified to have a multiple knots at the boundary was developed for the shell analysis and applied to the analysis of bridges. In the formulation of a non-symmetric spline finite strip method, the concepts of non-periodic B3-spline and a stress-resultant finite strip with drilling degrees of freedom for a shell are used. The introduction of non-symmetrically spaced knots in the longitudinal direction allows the selective local refinement to improve the accuracy of solution at the connections or at the location of concentrated load. A number of numerical tests were performed to prove the accuracy and efficiency of the present study.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.12C
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• pp.1239-1247
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• 2005

It is important to improve TCP performance in Self-similar TCP network where signalling between the same end nodes through bidirectional traffic routes. In wireless link, the traffic limitation pattern occurred in two or more TCP connections is applied into MPEC video control as multi time-interval congestion control. For TCP update variable, we extend TCP and perform as function call, and we study a method of relating TCP with LTS module controlling with the information type that is overcoming the limit of feedback loop determined by RTT. For comparison, we measure the TCP throughput without LTS and verify the fairness by means of meta control. The improved TCP performance is shown by that the number of connections of traffic congestion control increases when RTT increases.

• Journal of Korean Elementary Science Education
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• v.30 no.4
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• pp.468-481
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• 2011

This research is to observe and analyze the student interactions when inquiry problems were generated along with the students by using asynchronous discussion methods with the class bulletin board. For this research, 10 students from a single class of 6th grade were selected. The subject students were divided into 2 groups by cognitive levels. After the students were submitted the 4 problem situations for 1 week each, the discussion process was analyzed. The research results are as follows. First, the analysis of the step by step interactive discussion showed that several students answered for the question from a single student while discussing first for the question and answer in a form of a question with many multiple answers without any connections with the previously asked questions. At the end of the discussion, one to two students answered to a question by taking turns and the type of discussion changed to one question - one answer type by answering to the person who spoke prior to the next. Second, the discussion took place with the students in the transitional stage speaking in time in order, to provide comments to the bottom of the linear form and students in the formal operational stage students speaking in temporal order, regardless of the number of comments in the direction of the radiation(mind map) forms. The individual comment speaking rates were similar in the two groups so the students were able to speak indiscriminately.